Production and characterization of bacterial cellulose-alginate biocomposites as food packaging material

Biocomposite of bacterial cellulose-alginate has been developed for use as food packaging material. This study aims to understand the physical and mechanical properties of the biocomposite produced from static fermentation of Gluconacetobacter xylinus InaCC B404 in media supplemented with alginate. The strain was grown in a medium containing alginate at a concentration of 0.4, 0.8, and 1.2% w/v at 30oC for 7 days. The SEM images showed that bacterial cellulose produced in a medium supplemented with alginate had a denser structure of fibril network and a smaller pore size than the control one. The structure change was due to interactions through hydrogen bonds between bacterial cellulose and alginate proven by FTIR spectra, resulting in a decrease in crystallinity and crystallite size of bacterial cellulose. It led to the decrease in tensile and tear strength of the resulting biocomposite. Alginate also causes biocomposite to have higher water vapour permeability values.

OPTIMIZATION OF BACTERIAL CELLULOSE PRODUCTION FROM SUGAR BEET MOLASSES BY GLUCONACETOBACTER XYLINUS NRRL B-759 IN STATIC CULTURE

We investigated the optimization of bacterial cellulose (BC) production from sugar beet molasses by Gluconacetobacter xylinus NRRL B-759 in static culture. The optimization studies were performed using the central composite design (CCD) of response surface methodology (RSM). The independent variables were the molasses concentration, inoculation ratio and culture volume. The dependent variable was BC production yield. From the optimization tests, based on the model developed by RSM-ANOVA, it was found that binary interactions between molasses concentration–culture volume and inoculation ratio–culture volume had the most significant influence on the responses. The optimum conditions were as follows: 78.932 g/L molasses concentration, 12.973% inoculation ratio, and 130.405 mL of culture volume. The obtained BC was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and elemental analysis. The characterization results obtained in the study revealed that the produced BC exhibited typical FTIR spectrum, elemental composition, and nanofiber structure.

Optimasi Produksi Bacterial Nanocellulose dengan Metode Kultur Agitasi

Hampir sebanyak 90% industri farmasi di Indonesia masih menggunakan bahan baku impor. Indonesia memiliki salah satu bahan baku yang cukup melimpah yaitu selulosa. Bacterial nanocellulose (BNC) adalah hasil sintesis dari bakteri aerobic seperti bakteri asam asetat Gluconacetobacter spp. yang berbentuk selulosa murni dengan diameter berukuran nano. Bahan baku BNC yang digunakan dalam industri farmasi adalah BNC dalam bentuk slurry atau high viscose nanocellulose. Tujuan penelitian ini adalah untuk memilih bakteri dan kondisi optimum dalam memproduksi BNC. Bakteri yang digunakan adalah Gluconacetobacter xylinus dan Gluconacetobacter intermedius yang berasal dari InaCC-LIPI dan Gluconacetobacter sp. dari industri nata de coco. Inokulum dari ketiga jenis kultur bakteri tersebut dikultivasi selama 7 hari dalam medium Hestrin&Schramm (HS) cair menggunakan kultur statis dan agitasi dengan kecepatan pengadukan 150 rpm pada pH 5 dan suhu 25 ºC. Isolat bakteri Gluconacetobacter sp. dipilih sebagai bakteri penghasil BNC karena memiliki nilai yield paling tinggi. Kemudian isolat tersebut ditumbuhkan pada variasi kecepatan agitasi (100, 150, dan 200 rpm), variasi pH (4,0; 4,5; 5,0; dan 6,0), dan variasi suhu (25-30 ºC). Penelitian ini menunjukkan bahwa Gluconacetobacter sp. memiliki kondisi optimum pada kecepatan agitasi 150 rpm, pH 5,5, dan suhu 27 ºC. Optimization of Bacterial Nanocellulose Production in Agitation Culture MethodsAbstractAlmost 90% of pharmaceutical industry in Indonesia still uses imported raw material. However, Indonesia has one of the abundant raw materials which is cellulose. Bacterial nanocellulose (BNC) is a pure form of nanocellulose biopolymer material synthesized by microbes such as acetic acid bacteria of Gluconacetobacter spp. as pure cellulose and having diameter in nano scale. BNC used in pharmaceutical industry is in the slurry form/high viscose nanocellulose. The purpose of this study is to determine the bacteria and the optimum conditions to produce BNC. The bacteria used were Gluconacetobacter xylinus and Gluconacetobacter intermedius from InaCC-LIPI and Gluconacetobacter sp. from nata industry. The inoculums were cultivated for 7 days in liquid Hestrin & Schramm (HS) medium using static and agitation culture with a stirring speed of 150 rpm at pH 5 and temperature 25 ºC. The production of BNC has been conducted by using Gluconacetobacter sp., because it has the highest yield. Then it was inoculated at different variation of agitation speed (100, 150, and 200 rpm), pH (4.0; 4.5; 5.0; and 6.0), and temperature (25-30 ºC). This research shows that Gluconacetobacter sp. has optimum conditions at the agitation speed of 150 rpm, pH 5.5, and temperature 27 ºC.Keywords: Bacterial nanocellulose, Gluconacetobacter, agitation